Presentation Proposal for ELCE 2010 Name of Presenter: Harald Welte Title: Implmementing a Free Software telephone-side GSM protocol stack Presentation may be published: Yes Presentation may be video-recorded + published: Yes Brief Abstract: Recent years have seen a remarkable increase in Free Software running on smartphones. However, all such software is designed to run on the Application Processor (AP) only. The actual GSM protocol stack and RF Modem drivers are running as firmware on a completely different processor: The Baseband Processor (BP). OsmocomBB is a project developing the worlds first Free Software GSM protocol stack for the mobile phone side. It includes the hardare drivers for one particular GSM baseband processor chipset and replaces the vendor-provided firmware on compatible chipsets/phones. The presentation will introduce the challenges of doing this development in the environment of the arguably most closed part of the semiconductor industry, describe the software architecture and give a practical demonstration.